Exploring brainstem function in multiple sclerosis
In this study the researchers examined whether the diagnostic
sensitivity of clinical examination, evoked potentials (EPs) and
magnetic resonance imaging (MRI) can be improved by adding the
assessment of vestibulo-masseteric (VMR), acoustic-masseteric (AMR),
vestibulo-collic (VCR) and trigemino-collic (TCR) reflexes.
Sixty patients with relapsing remitting MS were selected. Patients
underwent clinical, neurophysiological and MRI evaluation within two
weeks. Controls underwent clinical examination and recording of
brainstem reflexes (BSRs). Neurological status was quantified with the
EDSS and Kurtzke’s functional system (FS) scores. MRI scans were
acquired with a 1.5 T Superconducting system. Global and regional FLAIR,
T2, STIR, T1 and T1-gadolinium enhancing lesion load was evaluated,
with a semiquantitative method, both for supratentorial-cerebellar
compartments and brainstem. Multimodal EPs of the visual (VEPs),
brainstem auditory (BAEPs) and somatosensory (median nerve stimulation:
mSEPs; tibial nerve stimulation: tSEPs) pathways were recorded. BSR
evaluation consisted in recording VMR and AMR from masseter muscles and
VCR and TCR from sternocleidomastoid muscles.
The results indicate that the paired use of the BSR/EP batteries is
associated to a detection accuracy of brainstem dysfunction, with
significantly higher sensitivity than that achieved by clinical and MRI
procedures taken together.
This finding supports previous findings of discrepancies between
neurophysiological data and both clinical and MRI evidence.
Demyelinating lesions can exist below the threshold for detection in
clinical examination and conventional MRI. This occurrence underlines
the value of such tests in detecting silent lesions. Conversely, subtle
lesions appearing in the MRI or producing clinical evidence of brainstem
involvement, but localized in brain areas non-critical for the
generation and/or synaptic transmission of the electric signal, are
sometimes insufficient to produce conduction neurophysiological
: Magnano I, Pes GM.
: Clin Neurophysiol. 2014 Mar 25. pii: S1388-2457(14)00166-7. doi: 10.1016/j.clinph.2014.03.016. [Epub ahead of print]
Read the abstract